When a leakage typically occurs on a high pressure value or a low temperature valve mounted in a pipe line for gas or fluid (e.g., petrochemical material or the like) due to abrasion or scratch of a sealing portion within the valve, emergency measures are taken by mounting three or four sealant fittings in one valve to allow not only a sealant for fluid interception to be rapidly injected but also a lubricant for keeping smooth operations and functions of the valve to be filled/injected if necessary.
In the meantime, according to the conventional sealant fitting, a sealant injection groove having a small diameter is disposed on an inner upper side of the body of the sealant fitting and a ball installation groove having a relatively large diameter is disposed below the body. A metal ball is closely adhered between the sealant injection groove and the ball installation groove and then a ball seat and a coil spring are disposed below the metal ball to allow the sealant to be injected and to facilitate performing a function of preventing a fluid back-flow. The body at the bottom surface of the spring is press-bent to form a sustaining part for preventing the spring from being deviated downward. A protrusion is formed at an upper portion of the body, which is unfastened when the sealant needs to be injected and is fastened (by cap nuts) to block the injection port when the sealant injection is completed. In addition, a punched vent cap is coupled to a vent groove by screws for smoothly discharging an internal air at the time of fastening operation, and a screw coupling part capable of being coupled to a large-sized valve by screws is formed at an outer lower side of the body.
However, according to the conventional sealant fitting as described above, the press-bent sustaining part for mounting the spring in the fitting, preventing the spring from being deviated and sustaining the bottom surface is disposed on the body at the bottom surface of the spring, so that the sustaining part is structurally weak. Such a sustaining part does not cause a significant problem when it is applied for a low pressure valve. However, the reliability of the sustaining part as a component of a high pressure valve or an ultra-low temperature valve is degraded when it is applied for the high pressure valve due to a high possibility of having cracks or damages in use.
In addition, the conventional sealant fitting is focused on the injection of sealant or lubricant that passes through the internal sealant injection groove and the installation groove, so that a possibility of allowing the fluid to be leaked or flown out of the outer screw part disposed at the lower position of the body still exists.
That is, even when an external screw thread of the lower screw coupling part disposed for easy coupling of the sealant fitting at a predetermined position of the valve is coupled with an internal screw thread of the valve by a strong coupling force, fine gaps and corrosion may occur when a high valve pressure is applied thereto or when the valve is used for a long time, resulting in a leakage of sealant, lubricant, fluid or gas.
In the meantime, many times, processes and costs are required for processing and manufacturing the vent cap and the ball seat among the components of the conventional sealant fitting, thereby decreasing the productivity, economical efficiency, quality and safety thereof.
That is, according to the vent cap among the components of the sealant fitting, its outer shape is of a hexagon nut as shown in the drawing, its each edge is chamfered, it has a coupling groove with a constant diameter therein, an internal screw thread formed on an inner wall of the coupling groove, a protrusion formed on its inner upper central end, and one or more vent grooves formed on its upper end.
To process this, an annular rod (including a hexagon rod) formed of a stainless or cast steel is first cut by a constant length, and twelve processes including a process for hexagon nut head of an outer surface of the vent cap, a process for upper edge, a process for lower edge, a chamfering process for hexagon nut head, a primary groove process for forming an inner coupling groove, a secondary groove process for forming a protrusion, a fine process for protrusion, a process for internal screw, a process for vent groove, a face milling process for upper surface, a face milling process for lower surface, and so on are carried out using a metal cutting tool such as shelf, milling or the like, so that many times and costs are unnecessarily consumed for the processing and manufacturing.
A process for internal groove, a process for lower spring sustaining part, a process for forming a groove for closely adhering the ball and the fluid communication, a chamfering process and so on are also required for processing the internal groove formed in the ball seat, the lower spring sustaining part, and the groove for closely adhering the ball and the fluid communication of the ball seat among the components of the sealant fitting, so that many processes and costs are consumed to decrease the economical efficiency and the price competition.
In addition, when the vent cap and the ball seat are manufactured using the conventional tools, the process quality is finely changed per each product when the process environment, an operator, an abrasion state of the tool or the like is changed, so that the quality safety and the uniformity are also degraded.
Further, the metal ball as an essential component for blocking or adjusting the fluid communication among the components of the sealant fitting is formed of a metallic material, so that it is very difficult to meet an accurate criteria such as the deviation from sphere, thereby not only limiting the function of blocking the fluid but also causing a high possibility of having scratches when the metal ball is in contact with other metal components.